Alfa Romeo 4C Forums banner
1 - 20 of 32 Posts

·
Registered
Joined
·
51 Posts
Discussion Starter · #1 ·
OK so I'm running into an issue with the timing belt change. Here's what happened:
  1. I followed the procedure exactly up to fitting the new belt and setting the tensioner at max tension. The only variation here is that I could only loosen the intake cam pulley bolt. I ruined two T55 sockets trying to pull off the exhaust pulley bolt, but I was careful and did not strip the bolt. So I only had the intake pulley loose when fitting the new belt.
  2. So here's where I screwed up: after I set the tensioner at max tension, I removed the locking tools without retightening the intake cam pulley bolt. As soon as the tools came off, the pulley rotated, the intake cam moved a bit and the tension went completely out of the belt.
  3. As soon as the locking tools were off I realized the mistake and tried to correct it by refitting the locks. I did not attempt to move the crank at all. I can refit the exhaust cam lock by just slightly bumping the cam to get the bolts to thread in, however it's clear that both the crank and intake cam have moved slightly. Based on my pictures it looks like the intake cam moved by about 5-10 degrees, and the same for the crankshaft (based on marks I made on it).
Anyone else mess this up, or have thoughts on how to fix this? The best I can think to do is to leave the exhaust cam locked, remove the tensioner and timing belt, then gently rotate the intake cam CCW back into position and refit the lock, and do the same for the crank. Given that they are slightly out of sync with the exhaust cam, I don't want to roll the engine over two times and risk damage.

Is that the smart way to do it? These tools should only go on in one position, so it seems like if I can get all three parts locked back in, I should still have proper timing. Or am I totally hosed?

Side note: the eLearn manual has nothing extra to add - even the procedure for dismantling the engine says to lock the cams in place before separating the head from the block, then on reassembly refit all the timing tools before installing the belt. This makes me think there are no other timing marks, even under the valve cover, and that as long as I have the locking tools fitted correctly, everything should be lined up.
 

·
Registered
Joined
·
250 Posts
I've done the belt a couple times, but haven't had anything like that happen so this is just a guess. I'd probably start with trying to rotate the intake cam CCW back into place (it's already swept that area, so likely no further damage doing that). I'm not sure what spring tension is in that position though. I'd probably try to fit the locking tool at that wrong angle, and see if I can use it to rotate the cam back. Failing that, I'd see if I can hold it while tightening up the cam bolt enough to be able to use the pulley as well to turn it ccw with the lock tool at the same time back into the locked position.
 

·
Registered
Joined
·
3,490 Posts
It sounds like you know what moved a few degrees and you're trying to stay in that window of a few degrees to move things back... but the problem with soliciting endorsement of this is that it's really hard to know exactly how off the timing really is and if you are really just moving it back to where everything really was. I think only you know. If any piston is at TDC or very close and you're off a few degrees, could parts try to operate in the same space within this few degrees of movement?

I am not aware of timing marks. It's really hard to endorse your next move here. Damn. No criticism, it's just that we want to be about as 100% certain as possible the timing isn't off enough to have bits hit eachother. Max confidence: It sounds like you should be ok to do as you say, but ugh.... that's not a ringing endorsement to do it.

Maybe someone at Alfaworks can help. Super helpful crew there or maybe ping @jamiealfa here
 

·
Registered
Joined
·
303 Posts
I don't have any problem endorsing your next move because I'm not the one doing the work so if you screw it up it is still your car and your fault... I'm not trying to be rude or snarky, just understand, if you don't know what you are doing or are not comfortable doing it, STOP! DON'T DO ANYTHING ELSE. At this point you have not damaged the car. If you are not comfortable with the next thing to do, stop, have the car towed to a reputable service facility, tell them what you have done and they will fix your car. What will probably hurt then is your wallet.

I have to assume a couple of things but I will try to cover the corrections. When you wrote about what you did you didn't say which way the crank and the cam rotated so I am going to assume they rotated in the normal "forward" direction they would turn if everything was connected and correctly timed. Having said that, you can certainly roll the cam and/or the crank BACKWARDS a few degrees to where they are supposed to be and lock them back in place with the special tools and resume your timing belt installation. Conversely, if they moved backwards simply roll them forward and re-install the locking devices.

Just for the record I actually didn't loosen either cam drive when I did my timing belt. The belt fit over the cam drives and like I have done so many times on the V-6s I've owned I rotated the crank backwards enough to install the belt. Then I rotate the crank back to the timing mark (or in the case of the 4C locking it back in place) and the tensioner takes out the slack. It has worked perfectly on the two 4Cs I've done and it usually works on the V-6s. I even did that on a 24v V-6 when I didn't have access to the proper cam lock tools. The important thing is that when you are finished and everything is re-tightened and you roll the engine over by hand that all of the timing marks line back up. It they do you are golden, if they don't you've make a mistake and need to start over.

In any event, what you are wanting to do is to put the cams and the crank back into their proper relationships so that you can install the belt and set the tensioner. The small amount the intake cam and the crank moved won't/doesn't matter, move them BACK (the opposite way they moved out of time) to the position where the locks can be re-installed. DO NOT rotate the engine, cam or crank. Simply put the cams and the crank back where they belong and install the locking tools, then resume your timing belt installation.

By the way, did you go out and buy a set of Ribe sockets for the four bolts on the crank pulley or did you just use a handy Torx bit that fit? Be careful you don't strip the drive in the those four bolts, they are different, they are not Torx. Northern Tools has the Ribe drivers on the shelf.
 

·
Registered
Joined
·
303 Posts
Just for the record I'm not going to debate how I installed the timing belts, I know there are going to be dissenters who say you can't do that or that is wrong, fine... I have been doing this for 40+ years and I know a few "tricks of the trade". As I said, the proof is rolling the engine over and rechecking the timing marks (or in the case of a 4C putting the three locks back in place). As long as that is done there shouldn't be any issues starting, running or revving the engine.
 

·
Registered
Joined
·
32 Posts
1. heat bolt with torch or heat gun and undo it.

now if space allows rotate camshaft with locking tool or something similar until it sits perfectly or remove cam cover and rotate camshaft with spanner if there is place to fit it or grips.

put it back as it should be done properly.
 

·
Registered
Joined
·
51 Posts
Discussion Starter · #7 ·
Thanks for all of the helpful suggestions; really appreciate it.

It sounds like you know what moved a few degrees and you're trying to stay in that window of a few degrees to move things back... but the problem with soliciting endorsement of this is that it's really hard to know exactly how off the timing really is and if you are really just moving it back to where everything really was. I think only you know. If any piston is at TDC or very close and you're off a few degrees, could parts try to operate in the same space within this few degrees of movement?

I am not aware of timing marks. It's really hard to endorse your next move here. Damn. No criticism, it's just that we want to be about as 100% certain as possible the timing isn't off enough to have bits hit eachother. Max confidence: It sounds like you should be ok to do as you say, but ugh.... that's not a ringing endorsement to do it.

Maybe someone at Alfaworks can help. Super helpful crew there or maybe ping @jamiealfa here
Thanks, definitely understand I'm making my own decision, just looking for ideas from everyone and making sure there isn't a better option.

I've done the belt a couple times, but haven't had anything like that happen so this is just a guess. I'd probably start with trying to rotate the intake cam CCW back into place (it's already swept that area, so likely no further damage doing that). I'm not sure what spring tension is in that position though. I'd probably try to fit the locking tool at that wrong angle, and see if I can use it to rotate the cam back. Failing that, I'd see if I can hold it while tightening up the cam bolt enough to be able to use the pulley as well to turn it ccw with the lock tool at the same time back into the locked position.
Thanks, good point on the cam having already swept that area.

I don't have any problem endorsing your next move because I'm not the one doing the work so if you screw it up it is still your car and your fault... I'm not trying to be rude or snarky, just understand, if you don't know what you are doing or are not comfortable doing it, STOP! DON'T DO ANYTHING ELSE. At this point you have not damaged the car. If you are not comfortable with the next thing to do, stop, have the car towed to a reputable service facility, tell them what you have done and they will fix your car. What will probably hurt then is your wallet.

I have to assume a couple of things but I will try to cover the corrections. When you wrote about what you did you didn't say which way the crank and the cam rotated so I am going to assume they rotated in the normal "forward" direction they would turn if everything was connected and correctly timed. Having said that, you can certainly roll the cam and/or the crank BACKWARDS a few degrees to where they are supposed to be and lock them back in place with the special tools and resume your timing belt installation. Conversely, if they moved backwards simply roll them forward and re-install the locking devices.

Just for the record I actually didn't loosen either cam drive when I did my timing belt. The belt fit over the cam drives and like I have done so many times on the V-6s I've owned I rotated the crank backwards enough to install the belt. Then I rotate the crank back to the timing mark (or in the case of the 4C locking it back in place) and the tensioner takes out the slack. It has worked perfectly on the two 4Cs I've done and it usually works on the V-6s. I even did that on a 24v V-6 when I didn't have access to the proper cam lock tools. The important thing is that when you are finished and everything is re-tightened and you roll the engine over by hand that all of the timing marks line back up. It they do you are golden, if they don't you've make a mistake and need to start over.

In any event, what you are wanting to do is to put the cams and the crank back into their proper relationships so that you can install the belt and set the tensioner. The small amount the intake cam and the crank moved won't/doesn't matter, move them BACK (the opposite way they moved out of time) to the position where the locks can be re-installed. DO NOT rotate the engine, cam or crank. Simply put the cams and the crank back where they belong and install the locking tools, then resume your timing belt installation.

By the way, did you go out and buy a set of Ribe sockets for the four bolts on the crank pulley or did you just use a handy Torx bit that fit? Be careful you don't strip the drive in the those four bolts, they are different, they are not Torx. Northern Tools has the Ribe drivers on the shelf.
You're right, as best I can tell both the intake cam and crank moved clockwise (i.e. forward). I think what you and @flyt100 are suggesting is the best path forward.

Regarding not loosening the cam pulleys, the first time I fit the belt, I actually didn't loosen them either, but once I had the new belt on and tensioned, then rotated the engine twice, all the tension went out of the belt and the exhaust cam didn't line up perfectly. So that's when I refit all the locking tools with the belt on (slightly rotating the exhaust cam CCW) and attempted to loosen the cam pulleys and all the above happened.

For reference, a couple of pics of the cam before/after:

This is right before I loosened the cam belt pulley (i.e. I believe still correctly timed). Note the position of the protrusions on the cam relative to the groove at 9 and 3 o'clock on the opening:


And this is right after the pulley came loose. Hard to get a pic from exactly the same angle, but you can see it rotated a bit. CCW in this picture is CW (forward) when looking from the front of the engine:



And with the cam lock inserted so you can see how far off it is. Note misalignment of the top holes:


Finally, the marks on the crank show it also moved forward (the silver paint marks were both at ~6 o'clock originally):
 

·
Registered
Joined
·
250 Posts
Out of curiosity where did the t55 bits snap? Were they 3/8 or 1/2"? I'm curious because those bolts are tight. Although I used 3/8 once, it was sketchy so I bought a 1/2 drive.
 

·
Registered
Joined
·
51 Posts
Discussion Starter · #9 ·
Out of curiosity where did the t55 bits snap? Were they 3/8 or 1/2"? I'm curious because those bolts are tight. Although I used 3/8 once, it was sketchy so I bought a 1/2 drive.
Both were brand-new 1/2" drive sockets. The first one failed when the splines or teeth of the Torx drive twisted. That was using a 1/2" breaker bar, ~18" long with a 12" cheater pipe on the end. The second one I attached to a 12" extension (1/2" drive) and hooked up to a corded electric impact wrench, which is good for about 450 ft-lbs. On that one the teeth look fine, but all that torque from the impact just hammered the socket sideways into the extension so they are now stuck together :cautious: Even that still didn't budge the bolt. I have nothing more powerful than that, so at this point I'm afraid I will just have to work around it.
 

·
Registered
Joined
·
721 Posts
I forgot which bolts, but I remember there are 6 bolts (or something like that) that look like Torx but are actually Ribe Bit
 

·
Registered
Joined
·
51 Posts
Discussion Starter · #15 ·
Thanks for all the suggestions... this weekend I'm going to pull the belt and line everything up where I think it should be and go from there. Will keep everyone posted once I fire it up again. Maybe I'll have a video of valve bits getting puked out of the exhaust :ROFLMAO:
 

·
Registered
Joined
·
51 Posts
Discussion Starter · #17 ·
Update with some good news, I think. 🤞🤞

I ended up locking the exhaust and crank, removing the belt, rotating the intake cam back to refit the lock, and then re-fitting the belt. I learned a couple of important things here, hopefully helpful for future DIYers:
  1. The biggest thing I learned is that when fitting the belt and before setting the tension, you have to make sure all the slack in the belt is on the side of the belt with the intake cam, water pump pulley, and tensioner. That way, when you set the tensioner it pulls all this slack out and it will hold tension when you rotate the engine. If you don't do it this way and leave slack between the exhaust pulley, idler, and crank, when you set the tension initially none of that slack gets pulled out. Then you rotate the engine and that slack works its way around to the tensioner, causing you to lose all the tension and the locks to not fit right. I'm pretty sure this is what caused some other members' issues with having to redo the tensioning procedure multiple times.
  2. Side note, @MultiAlfaOwner your trick with moving the crank backward slightly while fitting the belt was invaluable for taking the slack out. I backed the crank up just slightly, got the belt around as many pulleys as I could, then rolled it forward to re-fit the crank lock and fully fit the belt. That little bit of rolling forward takes all the slack out of the exhaust side of the belt. Thanks! 👍
  3. When refitting the belt for the second time, I decided to keep the intake cam pulley bolted tight. Unfortunately after getting the belt fitted, tensioned, and rotating the engine twice, I couldn't get all three tools on correctly. It was super close, but the bolts were clearly threading at an angle and no amount of bumping the crank/cams back and forth helped. I redid the whole procedure again (installing two locks, removing belt, moving the intake cam back to fit the final lock, etc.) but this time with the intake cam pulley loose, and it worked the third time. Bottom line is if you loosen the cam pulley(s), you need to leave it loose when refitting the belt, otherwise I think it can get misaligned by <1 tooth on the belt, since there is nothing to stop the pulley from spinning freely on the cam.
So now I'm at the point where I set tension to max, rotated the engine twice, got all the locks back on, reset tension, and then rolled it another 2 times to double check. All the locks fit perfectly, so I'm pretty sure I have the belt on and timing is correct. Won't know for sure until I turn it on and see if it spits intake valves out the exhaust though...

Two quick questions though: I was just re-reading the eLearn procedure to get the torque specs and noticed the manual says that the tensioner mounting bolt is supposed to have Loctite on it. The Alfa Workshop procedure does not mention this though. Has anyone else not put Loctite on there, or do I need to go back and do the whole thing again just to Loctite the bolt? 🤦‍♂️

Also, can anyone confirm I'm just supposed to replace the lost coolant by adding to the reservoir in the engine bay? I don't need to remove the hood to add coolant at the radiator cap, correct?
 

·
Registered
Joined
·
303 Posts
Me too! Very glad everything in good.

Tell a story on myself... Thirty-one years ago an exuberant blip to 6,500 rpm in my GTV-6 showed what happens to a timing belt that has had oil from original oil fed style tensioner leaking on it. It stripped the teeth. the belt didn't break but the teeth came off. $4,000.00 worth of engine damage and two years off the road were the results. Since then I am serious about timing belt maintenance.

Worst thing... The new belt and all of the new seals, o-rings and gaskets were sitting in the back seat when it happened. They were the week-end's planned maintenance, I was celebrating getting a new job.
 

·
Premium Member
Joined
·
9 Posts
Hats off to you folks tackling the timing belt replacement yourselves. I need to find a honest shop. I remember previous discussion threads included some San Francisco Bay Area 4C-owners recommending a couple independent shops on the peninsula. I’m hoping those owners are out there reading this and can jump in on this and send shop suggestions, again. Bear with me as I’ll post this same message on more than one thread on this subject.
 
1 - 20 of 32 Posts
Top